Boiler isn't my 'buddy', I don't know him, he's a random stranger on the internet. But personally I think your posts to him have been ruder than vice versa. I suspect the link about the wait times was simply a 'just in case you're not aware, this is how long the wait times are' - you'd be amazed how many people wouldn't know that there is a potential 2 year wait for an appointment and would think their relative would be over for a visit next month.
As for you being in the US meaning that your relatives visas are less likely to be approved, just have a hunt around the forum and see how many people have been refused B visas for suspected immigrant intent, or lack of ties to their home countries. Having you in the US makes that much more likely.
And yes, I agree that somebody not submitting their own application is fine but as you say that's for those who are illiterate or unable to complete their own applications - if that's the case then fair enough, but you haven't mentioned that being so. You completing the application for them if they were able to do so themselves just emphasises their tie to you which may not work in their favour. But this is all a guessing game, nobody knows for sure what will happen. My guess is that they will be refused a visa, as they have pretty much everything against them - US family, no money/resources, being from a high refusal country anyway, etc. But until they actually go for that interview, there's no way of knowing and sometimes there have been cases where people have surprised us and been given visas despite their circumstances. I wish them the best of luck.